Mutations in the m-AAA proteases AFG3L2 and SPG7 are causing isolated dominant optic atrophy.

OBJECTIVE: To improve the genetic diagnosis of dominant optic atrophy (DOA), the most frequently inherited optic nerve disease, and infer genotype-phenotype correlations. METHODS: Exonic sequences of 22 genes were screened by new-generation sequencing in patients with DOA who were investigated for ophthalmology, neurology, and brain MRI. RESULTS: We identified 7 and 8 new heterozygous pathogenic variants in SPG7 and AFG3L2. Both genes encode for mitochondrial matricial AAA (m-AAA) proteases, initially involved in recessive hereditary spastic paraplegia type 7 (HSP7) and dominant spinocerebellar ataxia 28 (SCA28), respectively. Notably, variants in AFG3L2 that result in DOA are located in different domains to those reported in SCA28, which likely explains the lack of clinical overlap between these 2 phenotypic manifestations. In comparison, the SPG7 variants identified in DOA are interspersed among those responsible for HSP7 in which optic neuropathy has previously been reported. CONCLUSIONS: Our results position SPG7 and AFG3L2 as candidate genes to be screened in DOA and indicate that regulation of mitochondrial protein homeostasis and maturation by m-AAA proteases are crucial for the maintenance of optic nerve physiology

Dominant ACO2 mutations are a frequent cause of isolated optic atrophy.

Biallelic mutations in ACO2, encoding the mitochondrial aconitase 2, have been identified in individuals with neurodegenerative syndromes, including infantile cerebellar retinal degeneration and recessive optic neuropathies (locus OPA9). By screening European cohorts of individuals with genetically unsolved inherited optic neuropathies, we identified 61 cases harbouring variants in ACO2, among whom 50 carried dominant mutations, emphasizing for the first time the important contribution of ACO2 monoallelic pathogenic variants to dominant optic atrophy. Analysis of the ophthalmological and clinical data revealed that recessive cases are affected more severely than dominant cases, while not significantly earlier. In addition, 27% of the recessive cases and 11% of the dominant cases manifested with extraocular features in addition to optic atrophy. In silico analyses of ACO2 variants predicted their deleterious impacts on ACO2 biophysical properties. Skin derived fibroblasts from patients harbouring dominant and recessive ACO2 mutations revealed a reduction of ACO2 abundance and enzymatic activity, and the impairment of the mitochondrial respiration using citrate and pyruvate as substrates, while the addition of other Krebs cycle intermediates restored a normal respiration, suggesting a possible short-cut adaptation of the tricarboxylic citric acid cycle. Analysis of the mitochondrial genome abundance disclosed a significant reduction of the mitochondrial DNA amount in all ACO2 fibroblasts. Overall, our data position ACO2 as the third most frequently mutated gene in autosomal inherited optic neuropathies, after OPA1 and WFS1, and emphasize the crucial involvement of the first steps of the Krebs cycle in the maintenance and survival of retinal ganglion cells

Autophagy protein 5 controls flow-dependent endothelial functions

Dysregulated autophagy is associated with cardiovascular and metabolic diseases, where impaired flow-mediated endothelial cell responses promote cardiovascular risk. The mechanism by which the autophagy machinery regulates endothelial functions is complex. We applied multi-omics approaches and in vitro and in vivo functional assays to decipher the diverse roles of autophagy in endothelial cells. We demonstrate that autophagy regulates VEGF-dependent VEGFR signaling and VEGFR-mediated and flow-mediated eNOS activation. Endothelial ATG5 deficiency in vivo results in selective loss of flow-induced vasodilation in mesenteric arteries and kidneys and increased cerebral and renal vascular resistance in vivo. We found a crucial pathophysiological role for autophagy in endothelial cells in flow-mediated outward arterial remodeling, prevention of neointima formation following wire injury, and recovery after myocardial infarction. Together, these findings unravel a fundamental role of autophagy in endothelial function, linking cell proteostasis to mechanosensing

Hand Hygiene Analyzed by Video Recording

International audienceObjective : The aim of this study is to evaluate the hand hygiene and isolation precaution adhesion of the healthcare workers in routine cares.Methods : In an infectious diseases care unit of a university hospital in Marseille, France, we designed an observational study at evaluating the hand hygiene and isolation precaution adhesion of the healthcare workers in routine cares by remote video recording. The care team including nurses, assistant nurses, housekeepers and physicians was monitored from November 30th (2012) to February 13th (2013). From a video camera was placed inside patient room, healthcare workers paths were recorded from entrance to exit of the patient’s room. Hand hygiene disinfection as well as gloves and mask wearing in isolation precautions were observed. A video camera was placed inside patient room. Healthcare workers paths were recorded from entrance to exit of the patient’s room. A nurse and a sociologist analyzed further videos. Hand hygiene disinfection as well as gloves and mask wearing in isolation precaution were observed.Results : A total of 756 videos were captures. 249 were rejected because they were not contributive and 507 videos (811 Healthcare workers paths) were analyzed. Healthcare workers had hand disinfection at least one time in the path in 28.2%. Hand disinfection at entrance and exit of the bedroom is respected in 6.2%. The meal tray delivery is associated with a lower hand hygiene practice. The glove wearing adhesion is 51.2% in Clostridium difficile contact precaution, and conformity to protocol is 17.5%. Wearing gloves impairs hand disinfection especially in situation where gloves are not part of the protocol (38.7%). Adhesion to mask wearing in airborne precaution is 90.7%

Hygiène des mains chez les soignants en milieu hospitalier : étude observationnelle par vidéo

L’hygiène des mains est un moyen efficace qui permet de limiter la transmission d’agents pathogènes. Malgré les nombreuses interventions, la non observance à l’hygiène des mains est en moyenne de 40 % [1]. Les audits interventionnels tels que préconisés par l’OMS basés sur le nombre d’opportunités de se désinfecter les mains présentent quelques biais. Notamment celui de la présence physique de l’auditeur qui a une influence directe sur le comportement des soignants (effet Hawthorne). MédiHandTrace® (MHT®) est un outil de traçabilité électronique automatisé par radio basse fréquence qui permet une identification des parcours des soignants en temps réel. Il permet aussi d’enregistrer les prises de solutions hydro-alcooliques par les personnels soignants à l’intérieur et à l’extérieur de la chambre.A l’occasion de la vérification de l’efficacité du système MHT® [2], nous avons utilisé la vidéo comme comparateur. Nous vous rapportons ici les résultats de l’étude des comportements tel qu’ils ont été observés par la vidéo.L’utilisation de la vidéo a pour objectif de comprendre, d’analyser les pratiques de soins, la désinfection des mains mais aussi d’identifier les facteurs qui en influencent la non observance

Women's perceptions and experience of adjuvant tamoxifen therapy account for their adherence: breast cancer patients' point of view

International audienceObjective: The aim of this study on primary breast cancer patients undergoing adjuvant tamoxifen treatment was to determine how their perceptions of the treatment and their experience of side-effects contributed to their adherence to the treatment. Methods: A consecutive series of primary breast cancer patients eligible for tamoxifen therapy were studied qualitatively by conducting semi-structured in-depth interviews at two French cancer centres. Results: The women aged 35-65 (N 5 34) were struggling with several issues involving their understanding and experience of the treatment, which have not been documented so far. These issues included confusion about the 'hormonal' nature and activity of tamoxifen and the etiology of the changes in their menopausal status, as well as the symbolic associations formed by patients about the paradox of taking a treatment that has aging effects but saves lives. Conclusions: This study shows the great physical burden often associated with tamoxifen treatment and brings to light women's own complex representations of the treatment and their interpretation of the side-effects. Better communication between health-care providers and patients should ultimately help to prevent refusal or discontinuation of tamoxifen treatment

High-throughput screening identifies suppressors of mitochondrial fragmentation in OPA1 fibroblasts.

Mutations in OPA1 cause autosomal dominant optic atrophy (DOA) as well as DOA+, a phenotype characterized by more severe neurological deficits. OPA1 deficiency causes mitochondrial fragmentation and also disrupts cristae, respiration, mitochondrial DNA (mtDNA) maintenance, and cell viability. It has not yet been established whether phenotypic severity can be modulated by genetic modifiers of OPA1. We screened the entire known mitochondrial proteome (1,531 genes) to identify genes that control mitochondrial morphology using a first-in-kind imaging pipeline. We identified 145 known and novel candidate genes whose depletion promoted elongation or fragmentation of the mitochondrial network in control fibroblasts and 91 in DOA+ patient fibroblasts that prevented mitochondrial fragmentation, including phosphatidyl glycerophosphate synthase (PGS1). PGS1 depletion reduces CL content in mitochondria and rebalances mitochondrial dynamics in OPA1-deficient fibroblasts by inhibiting mitochondrial fission, which improves defective respiration, but does not rescue mtDNA depletion, cristae dysmorphology, or apoptotic sensitivity. Our data reveal that the multifaceted roles of OPA1 in mitochondria can be functionally uncoupled by modulating mitochondrial lipid metabolism, providing novel insights into the cellular relevance of mitochondrial fragmentation

Metabolic Profile and Pathological Alterations in the Muscle of Patients with Early-Stage Amyotrophic Lateral Sclerosis

Diverse biomarkers and pathological alterations have been found in muscle of patients with Amyotrophic lateral sclerosis (ALS), but the relation between such alterations and dysfunction in energetic metabolism remains to be investigated. We established the metabolome of muscle and serum of ALS patients and correlated these findings with the clinical status and pathological alterations observed in the muscle. We obtained data from 20 controls and 17 ALS patients (disease duration: 9.4 ± 6.8 months). Multivariate metabolomics analysis identified a distinct serum metabolome for ALS compared to controls (p-CV-ANOVA SOD3 (p = 0.0017) and GLRX2(1) (p = 0.0022) in ALS muscle. Analysis of mitochondrial enzymatic activity in muscle revealed higher complex II/CS (p = 0.04) and lower LDH (p = 0.03) activity in ALS than in controls. Our study showed, for the first time, a global dysfunction in the muscle of early-stage ALS patients. Furthermore, we identified novel metabolites to be employed as biomarkers for diagnosis and prognosis of ALS patients